Adjusting means for the regulation of the intensity of sound for ear-phone receivers.



, R. J. BARBER. .ADJUSTING MEANS FOR THE REGULATION 0F SOUND FOR EAR PHONE 1909.

0F THE IN TENSITY RBGEIVERS APPLIoAToN FILED balza Patented Aug. 23, 1910.

fr?, vena 7 UNTTED sTATEs PATENT oEEIoE.

RAYMOND J. BARBER, F BELMONT, MASSACHUSETTS, ASSIGNOR T0 GLOBE EAR-PHONE COMPANY, 0F BOSTON, MASSACHUSETTS, A CORPORATION 0F MASSACHUSETTS.

,i ADJUSTING MEANS FOR `THE`IRIEGrUIMATION' OF THE INTENSITY OF SOUND FOR EAR- a PHONE RECEIVERS.

Specication of Letters Patent. Patented Aug'. 23, 1910.

Application filed october 26, 1909. Serial No. 524,606.

To all whom "it may concern:

Be it known that I, RAYMOND J. BARBER,v a citizen of the United States,

residing at Belmont, in the county of Middlesex and State of Massachusetts, have invented an Improvement in Adjusting Means for the Regulation of the Intensity of Sound for Ear-Phone Receivers, of which -the following description, in connection with theaccompanying drawings, is a specification, like letters on the drawings representing like parte.

One of the most important and at the same time difficult features in connection with earphone receivers is the regulation of the intensity of sound, and accordingly my invention resides in providing means for accomplishing this regulation without the possi.

llity of derangement of the mechanism due to careless or unskilled handling. The greatest intensity is secured when the diaphragm is approximately but not quite in contact with the poles of the electromagnet.v The adjustment necessary for securing the desired intensity is so exceedingly line that even the skilled vand careful expert in the factory has heretofore found it necessary to give special care and attention to this adjustment, and when the instrument has reached the hands 'of the inexperienced 'and often careless user, experience has proved that the instrument has been very liable to be condemned and thrown aside simply because this adjustment has been varied. Accordingly I have provided means rendering it impossible for the user to screw the diaphragm down too far or otherwise lose the original tine accurate adjustment. The diaphragm is mounted as usual in the cap or cover and is held permanently in fixed posit-ion thereini On the threaded rim of the body of the instrument, which receives the cap or cover with its contained diaphragm, I mount a knurled threaded ring and just back of this'ring a small smooth ring or stop which is likewise threaded in position and is adapted to be secured immovably in exactly the right adjustment by being pinned to the casing, the resultbeing that the user cannot possibly screw the diaphragm too close to the clcctromagnet so as to lose the ygreatest sound intensity'and yet he has it within his power, by adjustin the knurled ring outward, to decrease sai intensity acing in sidel elevation, partly broken away,

an earpho'ne receiver provided with my 4nvention; and Figs. 2 and 3 showing, 1n fragmentary cross section, details of the removable parts.

The general construction of the receiver may be of any usual or preferred kind, and hence I have omitted showing and describing the details of the internal construction.

The case 1 is externally threaded lto receive the correspondingly threaded portion of a cap or cover 4. In the latter the diaphragm 5 of the receiver. is clam ed by a threaded ring 6 between paper was ers 7, 8, holes 9 for a s anner Wrench being provided in ring 6. greatest intensity of soundy is secured when the diaphragm 5 is almost but not quite in contact with the poles l0, 11, of the electromagnet of the receiver, but the efficiency 'of the receiver is entirely killed if the diaphragm actually touches said poles. Hence s previously explained, the

tensitics of sound in order that the receiver shall be in accord vor tuned to the requirements ci their hearing, and hence there must be provision to enable the user to decrease said intensity from the maximum, and this is accomplished by moving the diaphragm away from. the electromagnet. Ac-

cordingly I provide a separate -knurled ring vl2 screwed onto the threaded portion of the case 1 in front of the cap to limit the adjustment of the cap when the latter is screwed onto the case.. By this means the i within proper rance, as h e may desire, and, while keeping said oif the cap and diaphragm .in case he Wishes to inspect the magnet, clean the salme, or the like. Having lnspected the magnet, he simply screws back the cap until it strikes against the ring 12 which was eft in the particular adjustment which he has found user is enabled to obtain such adjustment,

adjustment, may screw` by experience is suited to his hearing. Just back of the ring 12 I mount an adjustable stop in the form of a second threaded ring 13, preferably thin and of less external diameter than the ring 12 and having a smooth periphery 14 so that there is no tendency to grasp said ring inasmuch as the thicker ring 12 is knurled or milled and projects above the ring 13. 'This ring is provided at desired points throughout its periphery with radial pin holes 15. In adjustingthe ring 13, the cap 4 is turned onto the case 1 until the diaphragm 5 just touches the poles of the magnet. Thereupon the rings 12 and 13 are turned untilthey tighten` against the edge of the cap. A mark 16 is then made or noted opposite one ofl the pin holes l5 of the ring 13, the cap 4 and rin 12 are removed or turned backward slig tly and the ring 13 is then moved a short distance, as for instance to the point 17, where'- upon the pins are inserted in the pin -holes 15 and into the ease, permanently pinning the ring 13 immovably in said adjustment. When now the ring 12 is tightly screwed against the ring 13 and the cap screwed tightly inplace, the diaphragm will be as near the magnet poles aspossible without touching them, which is the point of greatent intensity of sound. The instrument is sent out in this adjustment and it will be evident that thereafter the user, Whether careless o'r careful, may freely vary the intensity of sound by adjusting the diaphragm by means of the ring 12 with reation to the magnet poles but cannot prcvent the proper working of the diaphragm by adjusting it against the poles. All the adjustment is secured by means of metal `(as distinguished from the non-dependable paper washers, for instance). and externally of the cap. The maximum adjustment toward the magnet is positive, so that screwing the diaphragm down too far is absolutely prevented. It is no longer necessary to leave a margin of safety in adjusting the apparatus but it can be set as fine as desired as the adjusting means is fixed and accurate. Y Having described my invention, what I claim as new and desire to secure by Letters Patent, is, i

1. In an ear-phone receiver, the combination with the case, its fixed magnet, and the cap and its diaphragm secured therein, said cap having threaded engagement with the case f'or adjusting said diaphragm toward and from saidmagnet, of an adjusting ring for limiting the adjustment of said cap on the case, a stop capable of adjustment on said case' in a direction toward and from the cap to vary the normal position of said ad justing ring and thereby vary the extent to which the cap can be screwed onto the case and meanssecuring said stop fast on the case in its said adjustment in position to limit the distance of possible approach of said diaphragm to said magnet.

2. In an apparatus of the kind described,

a case, a removable cap, one externally threaded and the other internally threaded for adjustment thereon, a diaphragm secured in fixed position in one, a magnet se cured in fixed position in the other for operating said diaphragm, and adjusting means for limiting the adjustment of said diaphragm and its carrying part with relation to said magnet tothe position of maximum intensity of sound, including a threaded stop adapted to travel on the threads of the-ease and means securing said stop in fixed posi tion in the path of movement of said diad phragm-carrying part with relation tothe magnet-carrying part to prevent the actual touching of the maglnetvby the diaphragm,

while permitting t almost together.

3.- In an apparatus of the kind described, a case, a removable cap, one externally threaded and the other internally threaded for adjustment thereon, a diaphragm secured in fixed position in one, a magnet see two to be brought cured in ixed position in the other for oper atin sai'd diaphragm, and adjusting means for imitin the adjustment of said diaphragm an its carrying part with relation to saidmagnet, including afreely movable threaded ring mounted upon the externally threaded member in the path of movement of said internally threaded member, and a stop ring back of said movable ring fixed in position to stop the movable ring-and internally threaded member when the diaphragm has reached the position of desired nearest rapproach to the magnet.

4. In an apparatus of the kind described, a case, a removable cap, one externally threaded and the other internally threaded for adjustment thereon, a ydiaphragm secured in fixed position in one, a magnet secured in fixed position in the other for operating said diaphragm, and adjusting means for limiting the adjustment of said diaphragm and its` carrying part with relation to said magnet, including a freely movable threaded ring mounted upon the externally threaded member in the path of movement of said internally threaded member, and a stop ring back of said movable ring fixed in position to stop the movable ring and internally threaded member when the diaphragm has reached the position of desired nearest approach to the magnet, said movable ring having a greater peripheral diametcrthan the stop ring. l

In an apparatus of the kind described, a case, a removable cap, one externally threaded and the other internally threaded for adjustment thereon, a diaphragm se` operating said diaphragm, and adjusting movable ring being peripherall knurled means for limiting the adjustment of said and having a greater periphera diameter diaphragm and its carrying part with relathan the stop rlng and the 'latter having a 15 tion to said magnet, including a freely movsmooth periphery.

able threaded ring mounted upon the ex- In testimony whereof, I have signed my ternally threaded member in the path of name to this specification, in the presence of movement of said externally threaded memtwo subscribing Witnesses.

ber, and a stop ring back of Said movable ring -xed in position to stop the movable RAYMCND J' BARBER' ring and internally threaded member when Witnesses: the diaphragm has reached the position of M. J. SPALDING,

desired nearest approach to the magnet, said EDWARD MAXWELL 

